The Compressed Bergen Overview
2NT shows a 4-card support raise with a wide range of HCP
Not a preemptive raise (<6 HCP), we use the double raise to the 3-level to show very weak hands, but with good trump support. This supports the idea that the law of total trump (9) should play best at the 3-level. Both as a probable making contract and to shut out the opponents from bidding. When we have a 9-card fit, the opponents likely have one as well.
You probably play (or are familiar with Jacoby 2NT (Game Force values and 4-card support raise) and Bergen Raises (4-card raise with 8-9 HCP and 4-card raise with 10-12 HCP). These Bergen raises are typically 3♣ and 3♦, and the weaker is determined by partnership agreement.
In our modern approach, we decided we could compress these three bids into a single response: 2NT.
2NT shows 4-card support for the opening major suit and more than a preemptive, weak hand. A wide range. The 2NT is a question bid back to the opener. It asks them the quality of their opening hand. To rate the quality, we ask the opener to calculate their hand's Losing Trick Count and bid at the 3-level to show the result.
- 3
- 5 LTC (aka a strong hand) - 3
- 6 LTC (aka a pretty good hand) - 3 of the bid Major - 7 LTC (minimal opening hand)
- 3 of the other Major - 4 LTC (aka a great hand, just short of opening with a strong 2 bid)
Why is this better than Jacoby+Bergen Raises
Those systems do work for most pairs. We have found that more precise communication of the LTC strength of the opening hand leads to more game contracts when Bergen bidders have to guess. We reach more secure slam contracts, and when the LTC calculation shows that we can safely play at the 5-level, we have options to explore for those slams that most pairs fail to find (or even consider)
Also, we free up the 3♣ and 3♦ bids for other purposes. Your partnership can use them to bid invitational hands and a 6-card minor. In Modern American, we use them for a SPLimit (or KRaise) raise (invitational raise, 3-card support, and unspecified short-splinter-suit). We use the 3♦ response to show exactly a 4333 shape hand, 3-card support, and game values. This is typically 3NT in standard bidding. 3♦ gives us some room for exploration when the opener has extra values.